Photoconductive element having an outermost layer of a fluorinated diamond-like carbon and method of making the same

Abstract

There is provided an electrophotographic element and method of making the electrophotographic element comprising a conductive support, a charge generation layer and a charge transport layer, said electrophotographic element having thereon a protective layer of a fluorinated diamond-like carbon wherein the fluorine content of the outermost surface of the fluorinated diamond-like carbon layer is between about 25 and about 65 atomic percent based on the total composition of the outermost surface of the protective layer. The protective layer provides for a low surface energy coating having a long process lifetime without causing latent image spread or degradation of photosensitivity.

What is claimed is: 
     
       1. An electrophotographic element comprising a conductive support, a charge generation layer, a charge transport layer comprising arylamine, and a diamond-like carbon layer having an outermost surface, wherein the fluorine content of said outermost surface of said diamond-like carbon layer is between 28.6 and 65 atomic percent based on the total composition of said outermost surface of said diamond-like carbon layer and wherein said outermost surface of said diamond-like carbon layer has a surface energy less than 40 mN/m. 
     
     
       2. An electrophotographic element according to claim 1 wherein said fluorine content is between 30 and 65 atomic percent. 
     
     
       3. An electrophotographic element according to claim 1 wherein the thickness of said diamond-like carbon layer is between about 0.05 and 0.5 micrometers. 
     
     
       4. An electrophotographic element according to claim 3 wherein the thickness of said diamond-like carbon layer is between about 0.15 and 0.2 micrometers. 
     
     
       5. An electrophotographic element according to claim 1 wherein said diamond-like carbon layer is a single layer. 
     
     
       6. An electrophotographic element according to claim 1 wherein said charge transport layer further comprises a polyester binder. 
     
     
       7. An electrophotographic element according to claim 1 wherein said outermost surface of said diamond-like carbon contains less than 20 atomic % oxygen, based on the total atomic composition of said outermost surface of said diamond-like carbon layer. 
     
     
       8. An electrophotographic element according to claim 1 wherein said charge generation layer is adjacent to said diamond-like carbon layer. 
     
     
       9. An electrophotographic element according to claim 1 wherein said charge transport layer is adjacent to said diamond-like carbon layer. 
     
     
       10. An electrophotographic element according to claim 1 wherein said charge generation layer comprises a charge generation material selected from the group consisting of dye polymer aggregates, phthalocyanines, squaraines, perylenes, azo-compounds, and trigonal selenium particles. 
     
     
       11. An electrophotographic element according to claim 1 wherein said charge generation layer comprises a dye polymer aggregate. 
     
     
       12. An electrophotographic element according to claim 1 wherein said arylamine is selected from the group consisting of triphenylamine; tri-p-tolylamine; N-N'-diphenyl-N,N'-bis-(3-methylphenyl)-(1,1'-biphenyl)-4,4'-diamine; 1,1-bis(di-4-tolylaminophenyl)cyclohexane; 4-(4-methoxystyryl)-4',4"-dimethoxytriphenylamine; N,N'-diphenyl-N,N'-di(m-tolyl)-p-benzidine, N,N',N",N'"-tetrakis(4-methylphenyl)-(1,1'-biphenyl)-4,4'-diamine; and mixtures of these materials. 
     
     
       13. An electrophotographic element according to claim 1 wherein said outermost surface of said diamond-like carbon layer has a surface energy less than 35 mN/m. 
     
     
       14. An electrophotographic element according to claim 1 wherein said outermost surface of said diamond-like carbon layer has a surface energy less than 25 mN/m. 
     
     
       15. A method of making an electrophotographic element comprising a conductive support, a charge generation layer, a charge transport layer, and a surface layer of diamond-like carbon, comprising the steps of: a) providing an electrically conductive support;   b) solvent coating over said support, in any order, charge transport and charge generation layers, the charge transport layer comprising arylamine;   c) allowing the solvent to evaporate; and   d) contacting the element formed in steps a), b), and c), in a reaction chamber, with a feed gas comprising a fluorocarbon compound in its gas phase and decomposing said compound by plasma-enhanced chemical vapor deposition to form a diamond-like carbon surface layer whose outermost surface has a fluorine content between 28.6 and 65 atomic percent based on the total composition of said outermost surface of said surface layer and wherein said outermost surface of said diamond-like carbon layer has a surface energy less than 40 mN/m.   
     
     
       16. A method according to claim 15 wherein said feed gas further comprises a gas or gaseous form of hydrogen or of a hydrocarbon compound. 
     
     
       17. A method according to claim 16 wherein said hydrocarbon compound is selected from the group consisting of paraffinic hydrocarbons represented by the formula C n  H 2n+2 , where n is 1 to 10; olefinic hydrocarbons represented by formula C n  H 2n , where n is 2 to 10; acetylenic hydrocarbons represented by C n  H 2n-2 , where n is 2 to 10; alicyclic hydrocarbons; aromatic compounds; and organic substituted compounds thereof. 
     
     
       18. A method according to claim 15 wherein said gas or gaseous form of fluorocarbon compound is selected from the group consisting of paraffinic fluorocarbons represented by the formula C n  F x  H y , where n is 1 to 10, x+y=2n+2, and x is 3 to 2n+2; olefinic fluorocarbons represented by the formula C n  F x  H y , where n is 2 to 10, x+y=2n, and x is 2 to 2n; acetylenic fluorocarbons represented by C n  F x  H y , where n is 2 to 10, x+y=2n-2, and x is 1 to 2n-2; alkyl metal fluorides; aryl fluorides; alicyclic fluorides; styrene fluorides; fluorine-substituted silanes; fluorinated ketones; fluorinated aldehydes; and organic substituted compounds thereof. 
     
     
       19. The method of claim 15 wherein said charge generation layer is adjacent to said a diamond-like carbon layer. 
     
     
       20. The method of claim 15 wherein said charge transport layer is adjacent to said diamond-like carbon layer.